Explosion proof by containment enclosure for housing electrical equipment

ABSTRACT

A low profile explosion proof by containment enclosure includes a base wall having first and second edge sections that are joined with third and fourth edge sections to define a substantially planar surface. First and second side walls extend from the first and second edge sections, and third and fourth side walls extending from the third and fourth edge sections and are joined with the first and second side walls. The base wall, first and second, and third and fourth side walls define an interior zone. A cover is coupled to the first and second, and third and fourth side walls to enclose the interior zone and provide containment to any flammable events. At least one of the first and second side walls, third and fourth side walls, base wall, and cover includes one or more unobstructed openings that provide fluid drainage while also providing containment to any flammable events.

BACKGROUND OF THE INVENTION

Exemplary embodiments pertain to the art of enclosures and, moreparticularly, to an explosion proof enclosure for housing electricalequipment.

Electrical housings or enclosures provide protection for electricalcontrollers, circuit boards, and the like. Often times, the enclosureand the electrical equipment are subjected to harsh operatingenvironments. Environmental elements such as wind, rain, humidity, dirt,and the like may all cause damage to electrical components. In additionto exposure to environmental elements, electrical equipment is oftentimes mounted in areas that are exposed to various flammable liquidsand/or gases that could be ignited if contacted by a spark or flame.When placed in environments that are exposed to flammable liquids and/orgases, electrical enclosures typically should be explosion proof byeither containment, ventilation or through a hermetic seal. In otherwords, any flame that may be ignited within the enclosure should not beallowed to exit to external, surrounding areas.

BRIEF DESCRIPTION OF THE INVENTION

Disclosed is a low profile explosion proof by containment enclosureincluding a base wall having first and second opposing edge sectionsthat are joined with third and fourth opposing edge sections to define asubstantially planar surface. First and second opposing side wallsextend from the first and second opposing edge sections, and third andfourth opposing side walls extending from the third and fourth opposingedge sections and are joined with the first and second opposing sidewalls. The base wall, first and second, and third and fourth opposingside walls define an interior zone. A cover is coupled to the first andsecond, and third and fourth opposing side walls. The cover is spacedfrom the base member so as to enclose the interior zone and providecontainment to any internal flammable events. At least one of the firstand second opposing side walls, third and fourth opposing side walls,base wall, and cover includes one or more unobstructed openings thatprovide fluid drainage while also providing containment to any internalflammable events.

Also disclosed is a method of relieving pressure in a low profileexplosion by containment enclosure having first and second, and thirdand fourth opposing side walls and a cover. The method includes allowingair to pass through one or more unobstructed openings formed in one ormore of the first and second, third and fourth opposing side walls, andcover. The openings are configured and disposed to prevent flames thatmay exist in an interior portion of the low profile explosion proof bycontainment enclosure from passing to an exterior of the low profileexplosion proof by containment enclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

The following descriptions should not be considered limiting in any way.With reference to the accompanying drawings, like elements are numberedalike:

FIG. 1 is a perspective view of a low profile explosion proof bycontainment enclosure in accordance with an exemplary embodiment;

FIG. 2 is a perspective view of a portion of the low profile explosionproof by containment enclosure of FIG. 1; and

FIG. 3 is a partial perspective view of a portion of the low profileexplosion proof by containment enclosure of FIG. 1.

DETAILED DESCRIPTION OF THE INVENTION

A detailed description of one or more embodiments of the disclosedapparatus and method are presented herein by way of exemplification andnot limitation with reference to the Figures.

Referring to FIGS. 1-3, a low profile explosion proof by containmentenclosure in accordance with an exemplary embodiment is indicatedgenerally at 2. Particularly shown in FIG. 2, low profile explosionproof by containment enclosure 2 includes a chassis 3 and a cover 4.Chassis 3 includes a base wall 5 having first and second opposing edgesections 6 and 7 that join with third and fourth opposing edge sections10 and 11 to define a substantially planar surface 14. Low profileexplosion proof by containment enclosure 2 is also shown to includefirst and second opposing side walls 20 and 21 that extend generallyperpendicularly from respective ones of first and second opposing edgesections 6 and 7. First side wall 20 includes a first end 24 thatextends to a second end 25. Similarly, second side wall 21 includes afirst end 26 that extends to a second end 27. First and second sidewalls 20, 21 define a length (L) of low profile explosion proof bycontainment enclosure 2 that is defined between, for example, first andsecond ends 26 and 27 of second sidewall 21.

Low profile explosion proof by containment enclosure 2 is further shownto include third and fourth opposing side walls 30 and 31 that extendsgenerally perpendicularly from respective ones of third and fourth edgesections 10 and 11. Third side wall 30 includes a first end 34 thatextends to a second end 35. Similarly, fourth side wall 31 includes afirst end 37 that extends to a second end 38. Third and fourth sidewalls 30, 31 define a width (W) of low profile explosion proof bycontainment enclosure 2 that is defined between, for example, first andsecond ends 37 and 38 of fourth sidewall 31. Low profile explosion proofby containment enclosure 2 also includes a height (H). At this point itshould be understood that the term low profile defines a profile inwhich both the length (L) and width (W) are substantially greater thanthe height (H). In accordance with one aspect of the exemplaryembodiment, the length (L) is about 15 times greater than height (H) andwidth (W) is about 10 times greater than height (H). Of course, itshould be understood, that the dimensions may vary. Base wall 5, firstand second opposing side wall 20, 21, and third and fourth opposing sidewalls 30, 31 collectively define an interior zone 48. Interior zone 48may be configured to house various electronic components such as printedwiring boards (PWB), controllers, computers and the like.

In further accordance with the exemplary embodiment, low profileexplosion proof by containment enclosure 2 includes a flange 54 thatextends about outer edge portions (not separately labeled) of first andsecond opposing side walls 20, 21 and third and fourth opposing sidewalls 30, 31. By outer edge, it should be understood that flange 54extends about an edge that is cantilevered from base wall 5. Flange 54includes a thickness (T) that is configured and disposed to prevent anyflames that may be present within interior zone 48 from passing to anexterior of low profile explosion proof by containment enclosure 2. Thatis, low profile explosion proof by containment enclosure 2 is configuredto be arranged in an environment that is exposed to flammable liquidand/or gases. In the event that a spark or other ignition event occurswithin interior zone 48 creating a flame, low profile explosion proof bycontainment enclosure 2 will prevent any flame from passing into theenvironment. In accordance with one aspect of the exemplary embodiment,flange 54 has a width (T) that is between about 0.667-inches (about16.94-mm) and about 0.780-inches (about 19.81-mm) Flange 54 is alsoshown to include a receiving portion 58 that receives a seal (not shown)which prevents moisture from entering interior zone 48.

In accordance with another aspect of the exemplary embodiment, flange 54includes a plurality of cover mounting elements, one of which isindicated at 60. Cover mounting elements 60 include threaded openings 62(FIG. 3) that are configured to receive threaded mechanical fasteners(not separately labeled). In addition, low profile explosion proof bycontainment enclosure 2 includes a plurality of cover mounting fastenerreceiver members, one of which is indicated at 67, that projectsubstantially perpendicularly from substantially planar surface 14. Eachcover mounting fastener receiver member 67 includes a central passage 75provided with a plurality of threads 76.

In accordance with yet another aspect of the exemplary embodiment, lowprofile explosion proof by containment enclosure 2 includes a pluralityof unobstructed openings 80-83. By unobstructed, it should be understoodthat openings 80-83 are devoid of any flame arresting structure, plugs,or the like. Openings provide an unobstructed flow path from interiorzone 48 to an exterior of low profile explosion proof by containmentenclosure 2. Opening 80 is arranged near first end 24 of first side wall20 and opening 81 is arranged near second end 25 of first side wall 20.Opening 82 is positioned adjacent first end 26 of second side wall 21and opening 83 is positioned near second end 27 of second side wall 21.Additional openings (not shown) may also be provided in third and fouropposing side walls 30 and 31.

As each unobstructed opening 80-83 is similarly formed, a detaileddescription will be made with reference to FIG. 3 in describing opening80 with an understanding that openings 81-83 include similar dimensions.Opening 80 includes a diameter 86. In accordance with one aspect of theexemplary embodiment, diameter 86 is between about 0.040-inches (about1.02-mm) and about 0.096-inches (about 2.44-mm) In accordance withanother aspect of the exemplary embodiment, diameter 86 is about0.060-inches. Each opening 86 also includes a length 88. In accordancewith one aspect of the exemplary embodiment, length 88 is between about0.125-inches (about 3.18 mm) and about 1.00-inches (about 25.4-mm) Inaccordance with another aspect of the exemplary embodiment, length 88 isabout 0.815-inches. Diameter 86 and length 88 define an aspect ratio foreach unobstructed opening 80-83. Unobstructed openings 80-83 arearranged to allow for fluid drainage when low profile explosion proof bycontainment enclosure 2 is arranged in various external environments andorientations.

In accordance with the exemplary embodiment, the aspect ratio for eachunobstructed openings 80-83 allows fluid to pass from interior zone 48to an exterior of low profile explosion proof by containment enclosure 2while at the same time preventing any flame that may be present withininterior zone 48 from passing to the exterior of low profile explosionproof by containment enclosure 2. In addition to allowing fluid todrain, unobstructed openings 80-83 provide pressure relief for lowprofile explosion proof by containment enclosure 2. More specifically,if mounted in an aircraft, low profile explosion proof by containmentenclosure 2 is exposed to altitude changes that may create pressurefluctuations within interior zone 48. Unobstructed openings 80-83 allowair to flow through interior zone 48 to prevent pressure build up.

In accordance with still another aspect of the exemplary embodiment, lowprofile explosion proof by containment enclosure 2 includes a cover 4.Cover 4 includes a cover body 103 having first and second opposing edgeportions 105 and 106 that join with third and fourth opposing edgeportions 109 and 110 to form a generally planar surface 114. Cover 4includes a first plurality of fastener openings 117 and a secondplurality of fastener openings 122. First plurality of fastener openings117 extend along first and second opposing edge portions 105 and 106 aswell as third and fourth opposing edge sections 109 and 110. Firstplurality of fastener openings 117 are configured to register with covermounting elements 60. In this manner, a plurality of mechanicalfasteners, one of which is shown at 125 are passed through firstplurality of cover mounting openings 117 and engaged with respectiveones of cover mounting elements 60 to secure an outer periphery of cover4 to flange 54. Second plurality of fastener openings 122 are arrangedcentrally on planar surface 114 and configured to register withcorresponding ones of cover mounting fastener receiver members 67. Cover4 and flange 54 combine to prevent any egress of flames that may bepresent within interior zone 48. Additional mechanical fasteners, one ofwhich is indicated at 130, are employed to secure a central portion ofcover 4 to base wall 5 through cover mounting fastener receiver members67. With this arrangement, cover 4 is prevented from bowing/flexingwhich may result from pressure caused by an internal flame.

At this point, it should be understood that the exemplary embodimentsprovide a low profile explosion proof by containment enclosure thatprevents any egress of flames within interior zone 48 while at the sametime providing pressure relief and fluid drainage. Fluid drainage andpressure relief is provided by one or more unobstructed openingsarranged on side walls of the low profile explosion proof by containmentenclosure. The use of unobstructed openings allows for liquid and/or airto flow from the interior zone without being constrained such as byclogging that might otherwise occur if flame arrestors or otherstructure is used to prevent flame egress. It should be understood thatwhile being described as having similar dimensions, the dimensions ofthe openings could vary. In addition to the opening, the particularwidth of the flange, combined with the cover, prevent flame egresswithout the need for complex flame extinguishing flow paths.

While the invention has been described with reference to an exemplaryembodiment or embodiments, it will be understood by those skilled in theart, that various changes may be made and equivalents may be substitutedfor elements thereof without departing from the scope of the invention.In addition, many modifications may be made to adapt a particularsituation or material to the teachings of the invention withoutdeparting from the essential scope thereof. Therefore, it is intendedthat the invention not be limited to the particular embodiment disclosedas the best mode contemplated for carrying out this invention, but thatthe invention will include all embodiments falling within the scope ofthe claims.

What is claimed is:
 1. A low profile explosion proof by containmentenclosure comprising: a base wall having first and second opposing edgesections that are joined with third and fourth opposing edge sections todefine a substantially planar surface; first and second opposing sidewalls extending from the first and second opposing edge sections; thirdand fourth opposing side walls extending from the third and fourthopposing edge sections and being joined with the first and secondopposing side walls, the base wall, first and second, and third andfourth opposing side walls defining an interior zone; and a covercoupled to the first and second, and third and fourth opposing sidewalls, the cover being spaced from the base wall so as to enclose theinterior zone and provide containment to any internal flammable events;wherein at least one of the first and second opposing side walls, thirdand fourth opposing side walls, base wall, and cover includes one ormore unobstructed openings that provide fluid drainage while alsoproviding containment to any internal flammable events.
 2. The lowprofile explosion proof by containment enclosure according to claim 1,further comprising a flange extending about the first and second, andthird and fourth opposing side walls, the flange having a thickness thatis configured and disposed to prevent any flames originating within theinterior zone from passing to an exterior of the low profile explosionproof by containment enclosure.
 3. The low profile explosion proof bycontainment enclosure according to claim 2, wherein the flange has athickness between about 0.667-inches (about 16.94-mm) and about0.780-inches (about 19.81-mm)
 4. The low profile explosion proof bycontainment enclosure according to claim 2, further comprising: aplurality of mechanical fasteners extending through the cover and intothe flange.
 5. The low profile explosion proof by containment enclosureaccording to claim 1, wherein the one or more unobstructed openingincludes at least two unobstructed openings in each of the first andsecond opposing side walls.
 6. The low profile explosion proof bycontainment enclosure according to claim 1, wherein the one or moreunobstructed openings includes a diameter of between about 0.040-inches(about 1.02-mm) and about 0.096-inches (about 2.44-mm)
 7. The lowprofile explosion proof by containment enclosure according to claim 6,wherein the one or more unobstructed openings includes a diameter ofabout 0.060-inches (about 1.52-mm)
 8. The low profile explosion proof bycontainment enclosure according to claim 1, wherein the one or moreunobstructed openings includes a length of between about 0.125-inches(about 3.18 mm) and about 1.0-inches (about 25.4-mm)
 9. The low profileexplosion proof by containment enclosure according to claim 8, whereinthe one or more unobstructed openings includes a length of about0.815-inches (about 20.7-mm)
 10. The low profile explosion proof bycontainment enclosure according to claim 1, further comprising: aplurality of fastener receiver members extending substantiallyperpendicularly outward from the base member, each of the plurality offastener receiver members including a central passage.
 11. The lowprofile explosion proof by containment enclosure according to claim 10,further comprising: a plurality of fastener openings formed in thecover, each of the plurality of fastener openings being registered witha corresponding one of the plurality of fastener receiver members. 12.The low profile explosion proof by containment enclosure according toclaim 11, wherein the central passage of each of the plurality offastener receiver members includes a plurality of threads.
 13. The lowprofile explosion proof by containment enclosure according to claim 12,further comprising: a plurality of mechanical fasteners extendingthrough corresponding ones of the plurality of fastener openings andthreadably engaging with the plurality of threads in each of theplurality of fastener receiver members.
 14. A method of relievingpressure in a low profile explosion by containment enclosure havingfirst and second, and third and fourth opposing side walls, the methodincluding: allowing air to pass through at least two unobstructedopenings formed in one or more of the first and second, and third andfourth opposing side walls, the openings being configured and disposedto prevent flames that may exist in an interior portion of the lowprofile explosion proof by containment enclosure from passing to anexterior of the low profile explosion proof by containment enclosure.15. The method of claim 14, further comprising: passing fluid throughthe at least two unobstructed openings from the interior portion of thelow profile explosion proof by containment enclosure.